Poland's President Bronislaw Komorowski expressed his concern over the escalation of political tensions in Kiev, Ukraine resulting in fatalities during violent clashes with police, while PM Donald Tusk said he would talk about the situation with the European Commission President.

At least four people have been shot dead and hundreds injured as demonstrators clashed with police over new laws limiting the right to protest in Ukraine. The clashes are an escalation of weeks of largely peaceful public protests against the decision of the Ukrainian President Victor Yanukovych to suspend work on a landmark association agreement with the European Union.

The country, which has championed Ukraine’s cause in the EU, is “concerned” about recent developments in Kiev, Komorowski said, speaking for Radio Zet broadcaster. “After Ukraine rejected the cooperation agreement with the EU, the room for maneuver is seriously limited - for Ukraine, the EU as well as for Poland,” Polish president added.

PM Tusk called on the international community for moderation in proposing sanctions against Ukraine, calling them a last resort.

He told a news conference that Poland has a “special role” as the EU’s mediator with Ukraine and wants to keep communication channels open with the government in Kiev. Tusk also said he will be pushing for a "responsible" use of sanctions against Ukraine when he speaks to the European Commission President. The current spread of violence in Kiev may have been a result of “provocation,” he added.

Poland's foreign ministry summoned the Ukrainian ambassador in Warsaw to voice its concern about the crackdown on anti-government protests in Kiev.

Among continued demonstrations, President Yanukovych met with the leaders of the opposition on Wednesday and agreed to continue talks about a potential dismissal of Mukola Azarov's government on Thursday.

One of opposition leaders, Vitali Klitschko, threatened with an "offensive" if the opposition's demands, including a special session of Parliament revoking the recently passed anti-democratic laws on public assemblies, are not met.

President Komorowski spoke with his Ukrainian counterpart and with Vitali Klitschko to discuss the situation.